High voltage three-phase circuit breaker module



March 29, 1966 D. A. LINK ETAL 3,243,558

HIGH VOLTAGE THREE-PHASE CIRCUIT BREAKER MODULE Filed May 29, 1963 V 2 Sheets-Sheet 1 March 29, 1966 D. A. LINK ETAL 3,243,553

HIGH VOLTAGE THREE-PHASE CIRCUIT BREAKER MODULE Filed May 29, .1963 2 Sheets-Sheet z United States Patent 3,243,558 HIGH VOLTAGE THREE-PHASE CIRCUIT BREAKER MODULE Donald A. Link, Menomonee Falls, and Albert C. Snowdon, Milwaukee, Wis., assignors to Cutler-Hammer,

Inc., Milwaukee, Wis., a corporation of Delaware Filed May 29, 1963, Ser. No. 284,103 2 Claims. (Cl. 200-144) This invention relates to circuit breakers of the type used in domestic and commercial service applications.

It is a primary object of the invention to provide a circuit breaker for relatively high voltage service within existing overall dimensions used for lower voltage circuit breakers.

Another object is to provide a circuit breaker of the aforementioned type which has enhanced dielectric life and are quenching ability through improvement and arrangement of materials used in the arcing region.

A further object is to provide an improved circuit breaker for special three-phase service using four of the aforementioned breakers with two thereof internally connected in series to afford double-break interruption of the power connection to one phase.

Other objects and advantages of the invention will hereinafter appear.

In the drawings:

FIGURE 1 is an end elevational view of four circuit breakers connected together in accordance with the invention;

FIG. 2 is a view of one of the circuit breakers taken along line 2--2 of FIG. 1;

FIG. 3 is a view of another of the circuit breakers taken along line 33 of FIG. 1;

FIG. 4 is an isometric view of certain components of the circuit breaker shown in FIG. 2;

FIG. 5 is an isometric view of certain components of a circuit breaker shown in FIG. 1; and

FIG. 6 is a diagrammatic illustration of the electrical connection of the breakers shown in FIG. 1.

Referring to FIG. 2, there is shown a circuit breaker with the cover removed as indicated by the line 22 in FIG. 1. Breakers 1 and 2 of FIG. 1 are alike and of the basic type described and claimed in the Martin F. Koenig et a1. United States Patent No. 3,081,386, dated March 12, 1963, and the copending application of Martin F. Koenig, Alexander J. Pastene and Lloyd D. Williams, Serial No. 261, 345, filed February 27, 1963. Therefore, a general description will be directed only to breaker 2.

There is shown a pivoted operating lever 6 mounted within the base of the breaker 2 and extending through an opening in the top of the base. The lower portion of lever 6 is divided into two spaced apart legs to provide space for a latch lever 8, and for the pivoted suspension of a movable contact member 10 and a latch 12. An overcenter coil spring 14 is attached at its one end to latch 8 and at its other end to movable contact member 10. A stationary contact member 16 is mounted within the base for engagement by movable contact member 10, and has clothes pin type leg portions extending through the base to afford electrical connection of the breaker to an external circuit.

Contacts 10a and 160 are attached to movable contact member 10 and stationary contact member 16 respectively. The surface area and mass of the contacts has been increased to provide a heat sink to cool the arc plasma and are spot and an enlarged surface conductive area to aid in ion recombination for deionizing the arc plasma. However, to provide for better arc interruption and to prevent the two contacts from welding together, their material is mismatched, that is, contact 26 upon overload of current within the breaker.

10a is of a material such as tungsten carbide silver while contact 16a is of a material such as silver tungsten. Contact 10a has the least heat conductivity of the two contacts, and therefore is placed on the movable contact member to gain the benefit of the air turbulence resulting from the movement of member 10.

An elongated flat armature 18 has a pair of outwardly extending ears at its upper end which are entrapped in a recess in the upper portion of the base and a like recess in a cover. Armature 18 is thereby pivoted within the breaker. Near its lower end armature 18 has a compensating bimetal element 20 welded to it to bias latch 12 into engagement with latch lever 8. Near its upper end armature 18 has a latch hook member 22 welded to it. Latch hook 22 extends through latch 12 to pull the latter out of engagement with latch lever 8 upon counterclockwise rotation of the armature.

A slide plate 24 is slidably entrapped within grooves in the lower portion of the base and cover and biased to the left by a compression spring 26. The lower end of the armature 18 is engaged within slots of slide plate 24 to follow the action of the plate under motion imparted by a bimetal element 28.

Bimetal element 28 also fits within a slot in slide plate 24, and moves it to the right against the biasof spring At its upper end, bimetal element 28 is welded to the upper end of an electrical connector member 30. Member 30 is held within the breaker by the configuration of the walls of the base and the cover, and by screw 32, which also is used to calibrate the breaker. Braided wire connectors welded at one end to the movable contact member 10 and at their other end to the bimetal element 28 complete the path of the circuit within the breaker.

A pole piece 29 is also mounted within the casing of the breaker, which comprises the base and cover, for magnetic operation of the breaker. Pole piece 29 is pivotally mounted at its upper ends by bosses on the base and cover which protrude into oblong holes in the pole piece. A hook portion 29a at the lower end of pole piece 29 extends into a recessed portion of the base and the left hand wall of that recess provides the clockwise limit of pole piece 29.

A common trip lever 34 is journaled in holes extending through the base and cover to cause tripping of adjacent breakers. Trip lever 34 has a fiat connector member 34a of insulating material mounted within a slot formed in the end of its bearing projection. Member 34a extends through the side of breaker 2 and the side of breaker 3 and into a corresponding groove in the trip lever of breaker 3. Each trip lever has a groove at each end and a like connection is made between trip lever 34 and the trip lever in breaker 1, and between the trip levers of breakers 3 and 4. As any one breaker trips, for example breaker 2, latch lever 8 rotates clockwise, strikes its trip lever 34, and imparts a clockwise rotation to the latter and to its associated trip levers which in turn force their armatures to the right and trip their breakers.

A pair of arc shields 36 and 38 (most clearly shown in FIG. 4) are fitted within the breaker in the area of the stationary and movable contacts. Arc shield 38 is a mirror image of arc shield 36. The contour of the bottom surfaces of the arc shield mates with surfaces in the base and cover, and ribs 36a and 38a formed on the outer surfaces of the shields mate with complementally formed slots in the base and cover of circuit breaker 2, respectively. On their inner surfaces, shields 36 and 38 have recesses 36b and 38b formed along the same line as ribs 36a and 38a. In one preferred form the arc shields are made of a commercially available are resisting material, such as #3251 Rosite, manufactured by the Rostone Corp., of Lafayette, Indiana, which has a high degree of arc-quenching ability and a very dielectric strength.

A blowout member 40 is made from a carbon steel bar which has a substantially square cross section and is bent in a U shape. The blowout member 40 is placed between the arc shields with its vertical legs partially disposed within the slots 36b and 3812. This reduces the erosion of the blowout member upon arcing of the breaker, and provides an additional brace, or support, member for the arc shields.

An insulating member 42 which has an L shape is positioned within the base between latch lever 8 and stationary contact member 16 to provide effective dielectric protection between the two members particularly during and after interruption of large overload currents. An insulating sleeve 44 is placed around overcenter spring 14 to protect the latter from the arc and to reduce any attraction of the are away from a vent opening 46 in the bottom of the base.

The breaker in FIG. 2 is shown in its on position. Let us assume that an overload condition exists, and that the current flowing through the breaker causes bimetal element 28 to move slide plate 24 to the right. Slide plate 24 pulls armature 18, and also latch book 22 to the right. Latch hook 22 pulls the latch 12 away from latch lever 8, and overcenter spring 14 pulls the latch lever downward and movable contact member away from the stationary contact member 16. Near the end of its travel, latch lever 8 strikes the common trip lever 34 to cause any other connected breakers to trip also, as described before.

When the movable contact member 10 moves away from the stationary contact member 16, an arc occurs between the two contacts 10a and 16a. As the arc shields are exposed to this arc, they emit a gas which deionizes the arc plasma. The high temperature of the are also renders the surfaces of the arc shields conductive due to its chemical composition which aids in the recombination of the ions. The blowout member pulls the arc away from the contacts toward its bight portion and toward vent 46, and in doing so, absorbs much of the heat, and aids in the ion recombination. Excess heated ionized arc plasma escapes through the vent opening 46, and creates an air turbulence which adds cool, deionizing air to the arc plasma. The metallic particles which usually litter an arc chamber due to expressive erosion of the blowout member have been greatly reduced by recessing the legs of the blowout member within the slots of the arc shields. Therefore the dielectric life of the device has been greatly enhanced. The combination of these parts within the standard size circuit breaker allow it to efiectively interrupt greater overload current flow at higher voltages.

FIG. 1 shows a circuit breaker designed to be used with three-phase circuits. Breaker 1 and breaker 2 of FIG. 1 are of the aforedescribed type shown in FIG. 2. Breakwers 3 and 4 are quite similar to breakers 1 and 2, however various modifications have been made to them.

In providing a circuit breaker for the third phase of a three-phase circuit, the clothes-pin type plug-in connector such as stationary contact member 16 (FIG. 2) is not utilized. Instead, connection is made through wire conductors to the screw terminal of connector members such as 30 located at the right hand end of the breaker assembly of FIG. 3. An insulating barrier portion 48 (-FIG. 3) is incorporated into the molded ,7 base of breakers 3 and 4 of FIG. 1 to insulate the contact area from the male portion of the hot line plug-in connection which exists on the mounting panel (not shown) for use with the aforementioned member 16. It can be seen that any venting now must be done through the opening in the lower right hand corner of the base (FIG. 3).

A number of arc interruption benefits have been lost due to this change in venting, and for this reason a double break is provided in the third-phase line.

As best seen in FIG. 5, the bases and covers of breakers 3 and 4 have been modified to provide for a stationary contact bar member 58 common to both breakers. The vertical wall of the base of breaker 3 has a raised surface which has a pair of substantially rectangular recesses 52a. The cover of breaker 3 has a rectangular opening 54 formed therein which is in alinement with the recesses 52a. The base of breaker 4 has a rectangular opening 56 (FIG. 3) corresponding to and in alinement'with opening 54 and the cover of breaker 4 has a raised surface and a pair of recesses formed on its vertical wall as a mirror image to that portion of the base of breaker 3.

The common stationary contact bar 58 has a pair of contacts 58a. (FIG. 5) welded to it. At its ends there is formed pairs of rectangular tabs 58b and 58c. Tabs 581) fit into recesses 52a and position that end of the bar 58 in breaker 3. Bar 58 extends through the openings 54 and 56 and tabs 58c fit into the recesses in the cover of breaker 4 which correspond to recesses 52a, therefore the other end of bar 58 is positioned in breaker 4. A thin insulator member 60 is placed around bar 58 at its center and is sandwiched between breakers 3 and 4.

Breaker 4 is shown in FIG. 3 with its cover removed. It can be seen that the arc shields 36 and 38, the blowout member 40, and the insulating sleeve 44 have also been removed, which is also true of breaker 3. The remainder of braker 3 is identical to breakers 1 and 2.

Breaker 4 ideally is identical to breaker 3, however to lower the cost of the breaker, it is modified as shown in FIG. 3. As can be seen it is very similar to the breaker 2 shown in FIG. 2 and like parts have been given like reference numerals. The overload responsive elements of breaker 4, that is, the bimetal member 28 and the pole piece 29, have been removed. Breaker 4, therefore, cannot respond to an overload condition on its own, but must rely on breaker 3 through its common trip lever connection 34a. Should both breaker 3 and breaker 4 have overload responsive elements, one would serve as a safety check on the other and the reliability would be twice as good, however, it can be seen that this is not necessary. It can also be seen that the braided wire connectors from movable contact member 10 are welded to the connector member 30 of breaker 4 in the absence of the bimetal member 28.

Each of the four breakers are individually assembled, and their covers secured to their bases by pairs of rivets 62 comprise the casing. The four breakers are secured.

together with the common stationary contact member 58 and insulating member 60 between breakers 3 and 4, and connector members 34a interconnecting the common trip levers 34 of each breaker, by a pair of rivets 64 which pass through all four breakers. The operating levers 6 of each breaker are interconnected by a U-shaped handle tie member 66 which provides a single, wide area handle for the assembly.

The depending leg portions of stationary contact member 16 of breakers 1 and 2 provide for the common plugin type connection to an external circuit. The third line, or phase, however, is connected to the screw type terminal of connector member 30 of breaker 4 as shown in FIG. 6. An overload in any line would cause all four breakers to trip open; however, the contacts of breakers 3 and 4 provided a double break in the third phase line thereby easily interrupting large overload currents which would otherwise be extremely difiicult due to the loss of venting benefits.

It will be understood that the foregoing description is only exemplary of the invention, and is susceptible to various changes by one skilled in the art without departing from the scope of the appended claims.

We claim:

1. A three-phase circuit breaker assembly comprising,

in combination, first and second pairs of circuit breakers, each breaker being of the type having an individual enclosing case, a spring biased over-center operating mechanism for operating the breaker contacts between circuitclosed and circuit-open condition, an operating lever for actuating said operating mechanisms, and a trip lever operable by said operating mechanism, said trip lever having portions accessible to the exterior of said enclosing case, wherein each breaker of said first pair of circuit breakers further comprises a vent opening formed in said enclosing case, trip means responsive to overload current conditions, a pair of arc quenching members positioned within the enclosing case on each side of the breaker contacts, said members having a recessed slot on their inner surfaces extending angularly downward from the area of the contacts and past the vent opening, a U-shaped blowout member having a square cross-section positioned within the breaker, the legs of said blowout member fitting within and substantially enveloped over three sides of their entire length by said recessed slots of said arc quenching members, and the bight portion of said blowout member extending between said are quenching members at the lower end of said recessed slots, and a cylindrical sleeve of insulating material surrounding the spring of said overcenter operating mechanism to reduce attraction of an are away from said vent opening, and wherein said second pair of circuit breakers have a common stationary contact bar extending through communicating openings in their enclosing cases, said contact bar having contacts secured to one face thereof at its ends, said contacts positioned within the respective enclosing cases in alinement with the respective movable contacts, and trip means responsive to overload current conditions in one of said second pair of circuit breakers, wherein each breaker of said first and second pairs of circuit breakers are secured together as a unit with means extending between each of said trip levers to rigidly link said trip levers together to form a common trip lever to cause all of the breakers to trip substantially simultaneously and means extending between the operating levers of each breaker to form a single common operating lever, and wherein the first and second phases of a three-phase load are connected individually to the breakers of said first pair of circuit breakers and the third phase thereof is connected in series to said second pair of circuit breakers to afford individual overload current sensing in each phase thereof.

2. A three-phase circuit breaker assembly comprising, in combination, first and second pairs of circuit breakers, each breaker being of the type having an individual enclosing case, a spring biased over-center operating mechanism for operating the breaker contacts between circuitclosed and circuit-open conditions, an operating lever for actuating said operating mechanism, and a trip lever operable by said operating mechanism, said trip lever having portions accessible to the exterior of said enclosing case, said first pair of circuit breakers each further comprising trip means responsive to overload current conditions and are quenching means in the area of the breaker contacts, said second pair of circuit breakers having a common stationary contact bar extending through communicating openings in their enclosing cases, said contact bar having contacts secured to one face theerof at its ends, said contacts positioned within the respective enclosing cases in alinement with the respective movable contacts, and trip means responsive to overload current conditions in one of said second pair of circuit breakers, wherein each of said breakers of said first and second pairs of circuit breakers are secured together as a unit with means extending between each of said trip levers t9 rigidly link said trip levers together to form a common trip lever to cause all of said breakers to trip substantially simultaneously and means extending between the operating levers of each breaker to form a single common operating lever, and wherein the first and second phases of a three-phase load are connected individually to the breakers of said first pair of circuit breakers and a third phase thereof is connected in series to said second pair of circuit breakers to afiord individual overload current sensing in each phase thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,156,761 5/1939 Jackson et al 200-116 2,882,372 4/1959 Preissler 200 3,071,666 1/1963 Ellsworth et al. 200147 3,102,937 9/1963 Brunner 200-147 3,152,287 10/1964 Edmunds 317-58 KATHLEEN H. CLAFFY, Primary Examiner.

P. E, CRAWFORD, Assistant Examiner. 

1. A THREE-PHASE CIRCUIT BREAKER ASSEMBLY COMPRISING, IN COMBINATION, FIRST AND SECOND PAIRS OF CIRCUIT BREAKERS, EACH BREAKER BEING OF THE TYPE HAVING AN INDIVIDUAL ENCLOSING CASE, A SPRING BIASED OVER-CENTER OPERATING MECHANISM FOR OPERATING THE BREAKER CONTACTS BETWEEN CIRCUITCLOSED AND CIRCUIT-OPEN CONDITION, AN OPERATING LEVER FOR ACTUATING SAID OPERATING MECHANISMS, AND A TRIP LEVER OPERABLE BY SAID OPERATING MECHANISM, SAID TRIP LEVER HAVING PORTIONS ACCESSIBLE TO THE EXTERIOR OF SAID ENCLOSING CASE, WHEREIN EACH BREAKER OF SAID FIRST PAIR OF CIRCUIT BREAKERS FURTHER COMPRISES A VENT OPENING FORMED IN SAID ENCLOSING CASE, TRIP MEANS RESPONSIVE TO OVERLOAD CURRENT CONDITIONS, A PAIR OF ARC QUENCHING MEMBERS POSITIONED WITHIN THE ENCLOSING CASE ON EACH SIDE OF THE BREAKER CONTACTS, SAID MEMBERS HAVING A RECESSED SLOT ON THEIR INNER SURFACES EXTENDING ANGULARLY DOWNWARD FROM THE AREA OF THE CONTACTS AND PAST THE VENT OPENING, A U-SHAPED BLOWOUT MEMBER HAVING A SQUARE CROSS-SECTION POSTIONED WITHIN THE BREAKER, THE LEGS OF SAID BLOWOUT MEMBER FITTING WITHIN AND SUBSTANTIALLY ENVELOPED OVER THREE SIDES OF THEIR ENTIRE LENGTH BY SAID RECESSED SLOTS OF SAID ARC QUENCHING MEMBERS, AND THE BIGHT PORTION OF SAID BLOWOUT MEMBER EXTENDING BETWEEN SAID ARC QUENCHING MEMBERS AT THE LOWER END OF SAID RECESSED SLOTS, AND CYLINDRICAL SLEEVE OF INSULATING MATERIAL SURROUNDING THE SPRING OF SAID OVERCENTER OPERATING MECHANISM TO REDUCE ATTRACTION OF AN ARC AWAY FROM SAID VENT OPENING, AND WHEREIN SAID SECOND PAIR OF CIRCUIT BREAKERS HAVE A COMMON STATIONARY CONTACT BAR EXTENDING THROUGH COMMUNICATING OPENINGS IN THEIR ENCLOSING CASES, SAID CONTACT BAR HAVING CONTACTS SECURED TO ONE FACE THEREOF AT ITS ENDS, SAID CONTACTS POSITIONED WITHIN THE RESPECTIVE ENCLOSING CASES IN ALINEMENT WITH RESPECTIVE MOVABLE CONTACTS, AND TRIP MEANS RESPONSIVE TO OVERLOAD CURRENT CONDITIONS IN ONE OF SAID SECOND PAIR OF CIRCUIT BREAKERS, WHEREIN EACH BREAKER OF SAID FIRST AND SECOND PAIRS OF CIRCUIT BREAKERS ARE SECURED TOGETHER AS A UNIT WITH MEANS EXTENDING BETWEEN EACH OF SAID TRIP LEVERS TO RIGIDLY LINK SAID TRIP LEVERS TOGETHER TO FORM A COMMON TRIP LEVER TO CAUSE ALL OF THE BREAKERS TO TRIP SUBSTANTIALLY SIMULTANEOUSLY AND MEANS EXTENDING BETWEEN THE OPERATING LEVERS OF EACH BREAKER TO FORM A SINGLE COMMON OPERATING LEVER, AND WHEREIN THE FIRST AND SECOND PHASES OF A THREE-PHASE LOAD ARE CONNECTED INDIVIDUALLY TO THE BREAKERS OF SAID FIRST PAIR OF CIRCUIT BREAKERS AND THE THIRD PHASE THEREOF IS CONNECTED IN SERIES TO SAID SECOND PAIR OF CIRCUIT BREAKERS T AFFORD INDIVIDUAL OVERLOAD CURRENT SENSING IN EACH PHASE THEREOF. 